Re: [PATCH] powerpc: _exception: kill the obsolete code under is_global_init()

Benjamin Herrenschmidt
2009-11-11T01:13:06Z

On Tue, 2009-11-10 at 01:25 +0100, Oleg Nesterov wrote:
> The code under "if (is_global_init())" is bogus, and is_global_init()
> itself is not right in mt case.
>
> Contrary to what the comment says, nowadays force_sig_info() does kill
> init even if the handler is SIG_DFL. Note that force_sig_info() clears
> SIGNAL_UNKILLABLE exactly for this case.
>
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
> ---

Thanks. I'll take that one.

Cheers,
Ben.

> arch/powerpc/kernel/traps.c | 22 ----------------------
> 1 file changed, 22 deletions(-)
>
> --- TH/arch/powerpc/kernel/traps.c~PPC_EXCEPTION_DONT_CK_INIT 2009-11-10 01:03:23.000000000 +0100
> +++ TH/arch/powerpc/kernel/traps.c 2009-11-10 01:06:41.000000000 +0100
> @@ -198,28 +198,6 @@ void _exception(int signr, struct pt_reg
> info.si_code = code;
> info.si_addr = (void __user *) addr;
> force_sig_info(signr, &info, current);
> -
> - /*
> - * Init gets no signals that it doesn't have a handler for.
> - * That's all very well, but if it has caused a synchronous
> - * exception and we ignore the resulting signal, it will just
> - * generate the same exception over and over again and we get
> - * nowhere. Better to kill it and let the kernel panic.
> - */
> - if (is_global_init(current)) {
> - __sighandler_t handler;
> -
> - spin_lock_irq(&current->sighand->siglock);
> - handler = current->sighand->action[signr-1].sa.sa_handler;
> - spin_unlock_irq(&current->sighand->siglock);
> - if (handler == SIG_DFL) {
> - /* init has generated a synchronous exception
> - and it doesn't have a handler for the signal */
> - printk(KERN_CRIT "init has generated signal %d "
> - "but has no handler for it\n", signr);
> - do_exit(signr);
> - }
> - }
> }
>
> #ifdef CONFIG_PPC64